Answer:
a. 
b. 
Step-by-step explanation:
First, we need tot find a general expression for the amount of caffeine remaining in the body after certain time. As the problem states that every hour x percent of caffeine leaves the body, we must substract that percentage from the initial quantity of caffeine, by each hour passing. That expression would be:

Then, to find the amount of caffeine metabolized per hour, we need to differentiate the previous equation. Following the differentiation rules we get:

The rate is negative as it represents the amount of caffeine leaving the body at certain time.
Answer:
6.28
Step-by-step explanation:
2 x 3.14
Answer:

Step-by-step explanation:
Using the change of base rule for logarithms
x =
( where c is the new base )
Given
log 17 , that is
17 , then
17 = 
Y=9x because if you divided y by x all the numbers will equal to 9 which is proportional